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<head>
    <title>Java后端WebSocket的Tomcat实现</title>
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Welcome SpringBoot学习－（十三）SpringBoot中建立WebSocket连接(STOMP) - CSDN博客
https://blog.csdn.net/qq_28988969/article/details/78113463 <br/><input id="text" type="text"/>
<button onclick="send()">发送消息</button>
<hr/>
<button onclick="closeWebSocket()">关闭WebSocket连接</button>
<hr/>
<div id="message"></div>
</body>

<script type="text/javascript">
  var websocket = null;
  //判断当前浏览器是否支持WebSocket
  if ('WebSocket' in window) {
    websocket = new WebSocket("ws://localhost:8080/webSocketServer?userId=wrwefesdfwetrwe324324");
  }
  else {
    alert('当前浏览器 Not support websocket')
  }

  //连接发生错误的回调方法
  websocket.onerror = function () {
    setMessageInnerHTML("WebSocket连接发生错误");
  };

  //连接成功建立的回调方法
  websocket.onopen = function () {
    setMessageInnerHTML("WebSocket连接成功");
  }

  //接收到消息的回调方法
  websocket.onmessage = function (event) {
    setMessageInnerHTML(event.data);
  }

  //连接关闭的回调方法
  websocket.onclose = function () {
    setMessageInnerHTML("WebSocket连接关闭");
  }

  //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
  window.onbeforeunload = function () {
    closeWebSocket();
  }

  //将消息显示在网页上
  function setMessageInnerHTML(innerHTML) {
    document.getElementById('message').innerHTML += innerHTML + '<br/>';
  }

  //关闭WebSocket连接
  function closeWebSocket() {
    websocket.close();
  }

  //发送消息
  function send() {
    var message = document.getElementById('text').value;
    websocket.send(message);
  }
</script>
</html>